1. Field of Invention
The field of the present invention is 3D modeling on a computer system. More specifically, the present invention concerns itself with a way to construct a 3D computer representation of a solid object given a number of 2D image xe2x80x9cslicesxe2x80x9d of the object.
2. Background of the Invention
There are many specialized techniques for creating image slices of real-world three-dimensional objects. In the medical imaging realm, for example, scanning devices relying on ultrasound, x-ray, and magnetic resonance technologies can be used to capture a series of image slices of various body structures as the scanning probe is moved slowly over the structure. However, assembling a 3D computer model of the structure from those 2D slices can be somewhat problematic.
The usual technique in prior art for constructing a 3D model of a solid object from a set of 2D image slices is to iteratively map each picture element (or pixel) (x,y) in each 2D image to a volume element (or voxel) (xxe2x80x2,yxe2x80x2,zxe2x80x2) in 3D space; given knowledge of the orientation of each 2D image slice relative to some fixed reference point (or the other image slices used to construct the 3D model), converting 2D pixels to 3D voxels is a relatively straight-forward mathematical exercise. However, it is a relatively expensive operation, computationally, and, hence, tends to be a very slow operation when done in software. (Commercial video acceleration boards for personal computers that do this sort of mapping in hardware are not commonly available.) Also, because voxels are typically represented using multiple floating-point values, building a 3D model this way on any computer system smaller than a high-end graphics workstation places a prohibitive load on system resources when constructing a model of any useful complexity.
Therefore, it would be useful to be able to construct a solid 3D model from a set of 2D image slices without mapping individual 2D image slice pixels directly to 3D voxels. Moreover, it would be desirable to be able to do this model creation in a way that takes advantage of widely available acceleration hardware circuitry.
Typical 3D display units that are based on voxels, particularly in the field of medical imaging, are limited in their ability to quickly manipulate the rotation, viewpoints, and appearance of 3D models in order to assist the user in identifying and/or diagnosing particular structures or anomalies. It is desirable to be able to perform such manipulations, particularly on commonly-available computing hardware.
The present invention is directed towards a computer-based 3D modeling system for constructing a virtual 3D representation from a plurality of data images of 2D cross sections having a mutual spatial relationship. The virtual 3D representation is constructed by extracting from a data source module the plurality of data images and the associated orientation and positioning information, creating a planar frame for each of the data images using a frame creation module, mapping each data image onto its corresponding frame as a texture using a texture-mapping module, rotating each planar frame according to the orientation information using a rotation transform module, and translating each planar frame according to the positioning information using a translation transform module.
Once the virtual 3D representation has been constructed, it may be rendered for purposes of review and/or manipulation. Review of the virtual 3D representation may be achieved by displaying it on a screen and performing one or more manipulations including rotating the representation, advancing into the representation using a clipping plane, adjusting the translucency, transparency, color, contrast, or brightness of the representation, resizing the representation, dynamically translating the viewpoint into the representation, or dynamically moving the viewpoint relative to the representation.